“They could be using the wrecks as rest stops along their migratory paths, but they could also be returning here for mating or possibly to give birth. There are all kinds of hypotheses our team is testing,” said Paxton in the report.

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Photos taken by the recreational divers and uploaded to the N.C. Aquarium’s Spot A Shark USA site revealed certain sharks were always at the same wrecks, the study says. The researchers made that discovery by “analyzing and comparing the spot patterns on sharks” in photos dating back 12 years, the study says.